Need to mount a samba share on your CentOS server from the command line?
Create a directory on the root:
mkdir /sharename
Then mount the share:
mount -t cifs //<servername>/<sharename> /sharename
if you type df -h you should see that your share is now mounted on the mountpoint that you created earlier.
Ever needed to connect to the remote console of the machine rather than running through a terminal services session so that you could install certain software, or reset stuck terminal services sessions from a remote location? All you have to do is type /console behind the host in the window.

To block an ip address from accessing your linux box, you can use the following iptables rule:
iptables -A INPUT -s 222.124.24.131 -j DROP
If you just need to block a certain port (i.e. port 22 for SSH), you would do it like so:
iptables -A INPUT -s 222.124.24.131 -p tcp --destination-port 22 -j DROP